Hi! Does anyone know what the typical nutrient uptake per day is from
plants? Chuck Gadd's calculator is great for figuring out how much of what
compound to reach target ppms...but if I don't know how quickly this is
being used up then it's either a guessing game or I have to test the water
every day with cheap inaccurate test kits or buy VERY VERY expensive lab
ones.

I did get this calculator http://www.fwstingrays.com/DosingCalculator.htm
....but it's assuming daily uptake is 4.5ppm NO3, 1.4ppm PO4, 3.4PPM K,
0.08PPM Fe...is this average? Also, that calculator gives a lot if
inaccurate/unbelievable suggestions for dosing...since I don't think all the
bugs are worked out---like for my 15 gal it's suggesting 11 ml of KH2PO4
every other day!! If the the calculator worked 100% then it would be
ingenius!

Right now I have 25-30ppm CO2, 2.67wpg, 6Gh, 15 gallon tank wide, 50% weekly
water changes.

Thanks

Dave.